Is standardised ¹⁸F-FDG uptake value an outcome predictor in patients with stage III non-small cell lung cancer?

Purpose: Recent studies have demonstrated the relevance of ¹⁸F-FDG uptake as an independent prognostic factor for recurrence of operable non-small cell lung cancer (NSCLC). This corresponds with the experimental finding that FDG uptake correlates with the proliferative activity of tumour cells (Higashi et al., J Nucl Med 2000;41:85-92). On the basis of these observations, we studied the influence of FDG uptake on prognosis and occurrence of distant metastases in patients with advanced NSCLC. Methods: One hundred and fifty-nine patients with NSCLC of UICC stage IIIA or IIIB were included in the study. In all patients, neoadjuvant treatment was planned to achieve operability. FDG PET was performed as an additional staging procedure prior to the initiation of therapy. Clinical outcome data in terms of overall survival, disease-free survival and incidence of distant metastases could be obtained for 137 patients and were correlated with the average standardised uptake value of the tumour (SUV_avg). Furthermore, other factors influencing SUV_avg and patient outcome (histological tumour type, grading, UICC stage, tumour size) were analysed. Results: SUV_avg was significantly influenced by tumour histology, UICC stage and tumour size. No significant difference could be shown for grading. In 38 out of the 159 patients (24%), FDG PET revealed previously unsuspected distant metastases. The incidence of distant metastases significantly correlated with SUV_avg. Overall survival tended to decrease with increasing SUV_avg; however, significance was only reached when a cut-off of 12.0 was applied (p=0.05). Conclusion: FDG uptake is an independent prognostic factor in patients with UICC stage III NSCLC, although less distinctively so than has been reported for stage I/II tumours.